52 Experimental Zoblogy 
I do not propose to consider in detail the cases that Darwin 
and Spencer have brought forward (most of them will not bear 
critical examination, as Weismann has so ably shown), but, as 
has been said, I shall consider rather those cases, most of them 
recent, in which attempts have been made by direct experiment 
to show that acquired characters are inherited. 
The work that has attracted most attention is that of Brown- 
Séquard. A full statement of Brown-Séquard’s experiments and 
results is given by Romanes in his book “Darwin and After 
Darwin,” Vol. IJ, Chap. IV. The experiments were made 
with guinea pigs. Epilepsy was induced by operations on 
some part of the nervous system. The young of these animals 
sometimes developed epilepsy, or some of its effects, in the same 
part of the body as that affected in the parent. The details of 
the experiments are as follows: The parents became epi- 
leptic after injury to the spinal cord or by section of the sciatic 
nerve. The “epileptiform habit” does not supervene until 
some time after the operation and lasts only ‘‘for some weeks 
or months.” The convulsions “never occur spontaneously, 
but only as a result of irritating a small area of skin behind the 
ear on the same side of the body as that on which the sciatic 
nerve had been divided.” + The attack lasts only a few minutes, 
and during this time the animal is unconscious and convulsed. 
The habit is only rarely transmitted to the young, but as the 
disease occurs only in guinea pigs whose parents have been 
made epileptic by an operation of the sort described above, 
and never in the young of guinea pigs that have been operated 
on in other ways, there seems to be here something more than 
a coincidence. 
Another series of experiments consisted in cutting the cervi- 
cal sympathetic nerve. This operation causes a change in the 
shape of the ear, and a similar change is said to appear in the 
young. By cutting the cervical sympathetic nerve or by re- 
moving the superior cervical ganglion, the eyelids partially 
close, and this closure was also seen in the young. 
* Romanes, “Darwin and After Darwin,” II, 1&g5. 
